I think it's a bad idea and would recommend grandparent to charge everyone for the service, then donate parts of the proceedings back to the Django project.
Great project. Looks like running outdated Django will be cheaper than running outdated rails... Although I can't remember if there were multiple players delivering "lts" versions for ruby/Rails?
I also want to experiment with reduced pricing for non-profits, but first have to get the basics down and ship the free and enterprise versions.
And then pay back a huge debt to Django with code contributions and corporate sponsorship.